Inter- and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord

Abstract

AIM: To assess inter-and intra-rater reliability (agree-ment) between two region of interest (ROI) methods in pediatric spinal cord diffusion tensor imaging (DTI). METHODS: Inner-Field-of-View DTI data previously acquired from ten pediatric healthy subjects (mean age = 12.10 years) was used to assess for reliability. ROIs were drawn by two neuroradiologists on each subject data twice within a 3-mo interval. ROIs were placed on axial B0 maps along the cervical spine using free-hand and fixed-size ROIs. Agreement analyses for fractional anisotropy (FA), axial diffusivity, radial diffusivity and mean diffusivity were performed using intra-class-corre-lation (ICC) and Cronbach's alpha statistical methods. RESULTS: Inter-and intra-rater agreement between the two ROI methods showed moderate (ICC = 0.5) to strong (ICC = 0.84). There were significant differences between raters in the number of pixels selected using free-hand ROIs (P < 0.05). However, no significant differences were observed in DTI parameter values. FA showed highest variability in ICC values (0.10-0.87). Cronbach's alpha showed moderate-high values for raters and ROI methods. CONCLUSION: The study showed that high reprodu-cibility in spinal cord DTI can be achieved, and demon- Retrospective Cohort Study strated the importance of setting detailed methodology for post-processing DTI data, specifically the placement of ROIs. Core tip: We tested the reliability of spinal cord diffusion tensor imaging (DTI) by assessing inter-and intra-rater agreement between two region of interest (ROI) selection methods. Results showed moderate to strong agreement between repeated measurements. There was a variation in DTI parameters at lower and upper spinal cord levels and significant differences between raters in the number of pixels they chose to outline ROIs. There were no significant differences in DTI parameter values derived from these ROIs. The study showed that strong reproducibility in spinal cord DTI can be achieved, and highlighted the importance of setting detailed methodology to standardize ROI drawing techniques. Barakat B, Shah P, Faro SH, Gaughan JP, Middleton D, Mulcahey MJ, Mohamed FB. Inter-and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord. World J Radiol 2015; 7(9): 279-285 Available from: